pistons

What is the difference between stepped pistons and flat compression wise? and wheres a good place to get like dome and specialty pistons and cams and cranks i was told by a great guy on here thats helped me some bullet was a good cam company

The compression of any piston is a function of how much volume it takes up in the combustion chamber. Some engines are designed with the compression chamber volume resulting from the piston being part way down the bore, (many diesels) some use a combustion chamber that is a slanted wedge between the top of the piston and an angled head surface (348-409 Chevy) Some rely on a pocket in the cylinder head Farmall M Gas, (most popular method)
So if we knew what you were working on, we could help a bunch more.
The more they take up compression chamber volume the higher the compression. Many use precision measuring methods to assess piston head volume. Jim

As Jim mentioned, domed pistons fill in the area fo the head's combustion chamber and increase the compression level. Flat tops don't lower compression ratios. Dished pistons, and they do exist, really lower compression ratios.

You have to be careful matching cranks, rods, pistons, cams, rocker arms, lifters. Figure that anything internal to an engine that moves needs to be matched, or complimentory of other components. Matching them may need to result in machining. The longer the rod throw, the closer to the head the piston dome gets and may require shaving the block for clearence. The longer the rod, the closer to the head the piston dome gets to the head. The higher the cam lift, the closer to the piston dome the valve face gets. Different rocker arm ratios will affect valve lift as well. All, or any of this may affect the clearances between the piston domes and the faces of the valves, which often requires the need to machine the piston domes for clearance. Higher compression ratios may require more heavy duty components such as connecting rods. Decking an engine block or heads to insure truing will affect a compression ratio and clearences.

You didn't mention your intended application. Field tractor? Garden tractor? Automotive? What is your intended desire or goal? There are all kinds of manufacturers of engine components, depending on the engine. There are all kinds of complete engine kits that might or might not require additional machining depending on the engine and intended application.

Good luck.

Mark

Thank you gracious and wonderful mark we are going to go back to pulling not no points comps just a few fairs and a few local tracks where we went and this thing hasnt been built restored but motor has the 1948 parts in it and we was pullin against guys that sounded like monster trucks in stock antique all right well i want to stock my daughters c up i just want to my back window decal "HOW DO YOU LIKE ME NOW "just a little friendly we are back and yes got the same little stock C o yes that is my daughter still driving we just thought we'd drop by and smoke you like a cuban cigar and we will be goin home

ok heres my brain storm a 123 super C block high dome pistons with a 240 head should come up around 45 hp there no head work no stroking cam nada just the 240 head 31/4 dome pistons pretty much yea a super c with overbore domes and a 240 head that should be bout 45hp then we can then maybe do a little shave here a little port and polish there maybe a little bigger bump stick. intake ? carb? Thats it the little tractor with bigger gonads since last time we but if this combo will work the gears will hold that much torque and hp and then later ill put her back stock after the fun

What ever pistons are used. If it"s a wedge head with a quench area . The flat portion of the piston should have a cold clearance of 30-40 thou to the head.
Otherwise the squish and turbulence is lost. Engine will tend to knock more and require much higher octane fuel.
Pistons alone won"t do it. The cam and followers will be worn. Tell the cam grinder the intended application and the octane of the fuel being used. The cam grinder will spec the cam and compression ratio.
Three angle valve job too.